The Lady and the Unicorn tapestry, made at the end of the 15th century, was acquired by the Musée de Cluny in 1882. The set consists of 6 tapestries representing an allegory of the five senses and another sixth sense which is still debated. Since their discovery, they have undergone more than a dozen restoration campaigns. These have been more or less documented in written sources. For example, the horizontal band at the bottom of the tapestries was made during the 1889 restoration by Jules André Lavaux, a tapestry weaver who worked both for the Gobelins manufactory and as an independent weaver. For its reweaving, scrap wool, dyed by the workshop of the Gobelins manufactory, would have been used. Nowadays, the fading of dyes results in a very visible restoration that stands out from the rest of the medieval tapestry.The considerable state of degradation of this restoration has challenged us to study it with non-invasive and contactless methods (colorimetry, optical microscopy, hyperspectral imaging [VIS and SWIR] and fluorimetry). These methods have allowed the characterisation of the materials used during the restoration and have given rise to a discussion on the ethics of restoration in the 19th century by confronting these results with the written sources discovered in the archives. It has also been an opportunity to evaluate the capacity of our methods and data processing in the context of a heavily restored textile work.The tapestry named "Mon seul désir" was studied during its exhibition at the Musée des Abattoirs in Toulouse (France) in November 2021. The analysis of the main colours (red, blue, yellow and green) has allowed the identification of natural dyes (madder, woad, weld). The entanglement of the wool threads has revealed unexpected restoration techniques. For example, for the red of the background, red and yellow fibres were used. For the blue tint, it was a weaving of blue and white wool thread that was chosen. The impact of this restoration technique can be seen with hyperspectral data on the acquired spectra. This is discussed as a new way for data processing. These preliminary results depend on our knowledge of this medieval masterpiece (e.g. materials used during its production) as well as its enigmatic restoration (revelation of the restoration methods and materials used).< Réduire